Thunderstorms are a major weather hazard, but are difficult to predict. They can travel at speeds of 20 km/h to 40 km/h, and lightning strokes may occur more than 10 km in front of the rain clouds and equally some distance behind the rain clouds. While a lightning stroke is produced by a cloud or a weather front, many of the most dangerous lightning strokes actually occur when no visible clouds are present above as a warning of thunderstorm. Thus, a system that warns of possibility harmful thunderstorms, even if only approximately ten minutes before they become visible, can be considered a major safety feature.
There is a large population that would benefit from such a safety feature. To some persons, it might provide only a nice-to-know everyday knowledge. To a considerable number of persons, however, storm and lightning originated threats have significant implications in the form of an increased risk, loss of property or even fatal consequences. A lightning alerting system is of particular interest, for instance, for persons spending much time outdoors, and equally for aviators, navigators or the like. A system providing a warning of lightning even when the weather seems to be perfectly calm and clear may enable a person to take suitable safety measures in time, for instance seek shelter etc.
From the state of the art, many single-purpose lightning detectors are known, but they have some disadvantages from a commercial perspective.
Scientific lightning detectors, which are used in meteorology, are very large and their range is hundreds of kilometers.
Also other high-end lightning detectors using a single radio frequency (RF) band are large and relatively expensive, compared for instance to mobile phones. Moreover, they are usually required to have a specific orientation, for instance standing on a wall or on a desk stand, in order to gain the required accuracy or directionality. They are thus not well suited for a truly mobile use. These devices typically have further to be vertically positioned and held stable for several minutes before a reliable detection of a thunderstorm libecomes possible.
In addition, there are now existing rather inexpensive lowend lightning detectors which are completely portable in size and which do not require a specific orientation. These detectors, however, are extremely susceptible to electromagnetic compatibility (EMC) emissions and thus tend to cause spurious alarms especially in an urban setting or near highways, etc.